Charles Robert Powers, nicknamed Chef, had been in Santa Cruz for a few years, police said. He knew and had camped with the three men and two women arrested in his slaying, and police said they had an argument before he was attacked.

Police said Tuesday that the investigation focused on 26-year-old transient Jeremiah James Long, one of the five suspects arrested on suspicion of murder and conspiracy.

Long has the longest rap sheet of the group, including battery convictions in 2006 and 2007, according to Santa Cruz County court records. Long's record also includes convictions for attempted grand theft, petty theft, drug possession, public intoxication, and stay-away orders from a supermarket, pizza restaurant and three streets near downtown.

Four others also have been arrested on suspicion of murder and conspiracy: Shaelyn Zeanne Gonzales, 21, of Capitola; Michael Valgene Hudson, 41; Jason Michael Weiland, 31; and Tina Anderson, 43, all transients.

All but Anderson were on probation for drug-related crimes at the time of the attack, authorities said.

Clark said detectives have a theory about the motive, but they are still arranging pieces in the puzzle. A skateboard police believe was used in the attack was among 159 items collected as evidence.

"It's incredibly difficult dealing with these people," Deputy Police Chief Steve Clark said of the suspects. "These are people who deal with a lifestyle of drug abuse."

They threw rocks at Powers, knocking him to the ground, police said. Then, one of them struck him with a skateboard.

Powers was found dead near the railroad tracks just before 11 p.m. Friday.

Police identified Powers on Tuesday because they contacted his brother and son in Tennessee.

Powers' last known address was in Santa Cruz, but he also had a post office box in Freedom. A friend of Powers, Jennifer Rodriguez, said Powers was a good person who often talked about his cooking skills.

Powers worked at a restaurant at some point. He did not have a criminal record in Santa Cruz County, but police wrote him a ticket in September for smoking on the beach.

Powers' alleged attackers all had been in trouble with the law.

Hudson pleaded guilty in July 2011 to felony drug possession and was sentenced to three years' probation, according to court records.

He also had been convicted of petty theft from a supermarket that year and misdemeanor fighting in a public place in 2010, records show. Hudson was sentenced to one year of probation in each case.

Weiland was arrested twice this year on suspicion of drug possession and convicted on one of the charges, according to records. He also was convicted in October of possession or manufacture of a dangerous weapon and sentenced to six days in County Jail.

Gonzales pleaded guilty to felony drug possession in July and was sentenced to fines, drug rehabilitation and three years' probation. She also was caught with more than 1 ounce of marijuana in 2011 and fined $274 for the infraction. She never paid it, records show.

Anderson, a self-described sheep farmer, had no criminal record but had about 20 infractions for city violations such as illegal camping and being in a park after dark.

Santa Cruz police spokesman Zach Friend said detectives now are trying to reach two men and a woman who might have more information.

Detectives continue to interview witnesses and are "trying to track down someone who would hold the clues to why this started," he said.